(A & B) Time course of individual HTLV-1 RNA transcripts for PMA-treated (solid lines) or untreated (dashed lines) FS cells (A) and SP cells (B), measured by quantitative reverse transcription-PCR (RT-qPCR) using splice site-specific primers (Supplementary file 2: Supplementary Table S1). Blue diamonds, tax/rex mRNA; Red squares, gag/pol (unspliced) mRNA; green triangles, env mRNA; purple diamonds, p30 mRNA; and yellow diamonds, HBZ mRNA (spliced form). Data are normalized to Ct values for ASL mRNA, and divided by the value obtained for the zero time point. Cells were treated with PMA for one hour, washed and resuspended in fresh media, and harvested for RNA and protein isolation at indicated time points. Stimulation of latently infected cell lines induces a rapid, but transient, increase in tax/rex mRNA that precedes other HTLV-1 mRNA species. (C & D) Western blots for protein extracts of PMA-treated and untreated FS cells (C) and SP cells (D). Overall, induction of HTLV-1 protein levels resembles that of mRNA induction.